The 10 percent that stops your application being rejected
Module wattages never divide neatly into system sizes, and applications were being rejected for it. MNRE now allows a tolerance on declared DC capacity.
Topic
Design
Roof capture, shading analysis, stringing, inverter sizing and layout decisions that determine whether a rooftop system performs as quoted.
RCC, metal sheet and asbestos are three different jobs
The roof decides the structure, the fixing, the safety plan and the price. What to check on each type before you quote, and when to walk away from one.
The structure is the part that has to last 25 years
Modules are warranted for decades and the structure holding them often is not. Wind uplift, edge zones, ballast against anchoring, and corrosion near the coast.
One ohm, and the fire that starts in a connector
Earthing is the one thing every DISCOM inspector physically checks, and loose DC connectors are how rooftop systems catch fire. The practice that prevents both.
TOPCon, bifacial, and what actually belongs on a rooftop
TOPCon has taken over Indian rooftop supply and bifacial is sold with it. One of those choices is usually right and the other usually is not, on a house roof.
Why the system generates less than you promised
Nine reasons an estimate and a meter disagree, how to tell which one is at fault, and what to put in writing so the conversation never becomes an argument.
Stringing rules of thumb that stop working on Indian rooftops
String length is decided by the coldest morning, not the hottest afternoon. The voltage arithmetic, the MPPT rules, and the mistakes that show up in year two.
Dust costs more than most EPCs think, and cleaning costs less
Soiling runs from about 6 percent on the coast to 15 percent in arid zones. The arithmetic of cleaning frequency, and who should be doing it after handover.
Why the array should be bigger than the inverter
A 5 kW inverter under 6 kW of modules is not a mistake. What the DC to AC ratio does to annual generation, where it helps most, and where oversizing stops paying.
Sanctioned load is the ceiling nobody checks until sanction
Most DISCOMs will not sanction a system larger than the connection's sanctioned load. How to spot it on the bill, and what enhancement really costs a customer.
Bill of materials mistakes that eat a signed job's margin
The margin on a rooftop job is usually lost after signature, in items nobody priced. Fourteen line items that go missing, and the two clauses that protect you.
New CEA standards land in April 2027. Check your BOM
The CEA notified amended technical standards in July 2026, effective April 2027: 25 year design life, bypass diodes and salt mist testing near the coast.
Sizing a system from the customer's electricity bill
The bill carries six numbers that decide system size, and most site visits read only one. How to size a rooftop system before you have measured the roof.
Maharashtra wants a battery on every job above 100 kW
New rooftop solar above 100 kW in Maharashtra must carry storage at half the solar capacity for two hours. How to size it, quote it and explain what it costs.
Shading analysis without guesswork
A parapet, a water tank and a staircase room can cost more generation than a module upgrade recovers. How to measure shade on site and design around it honestly.
DCR and ALMM List-II are not the same rule
Non-DCR modules are not banned outright. Which rule applies to which project, and why the net metering exemption expiring on 31 December 2026 matters.
How to close a rooftop deal on the first site visit
The gap between the site visit and the proposal is where rooftop deals go cold. What to produce on the roof, and what to stop doing back at the office.